This invention relates to a multi-station data transmission system in which the stations are interconnected by optical fiber links.
A closed-loop system of the type to which the invention is applicable is shown in FIG. 1, in which there are a number of terminals such as T each connected to the loop via a repeater R. As will be seen, each terminal T is provided with a repeater R, and in addition, especially where the distance between two terminals is relatively long, there may be one or more repeaters RX which are not associated with terminals. Finally, one of the terminals such as terminal TM functions as a master terminal, but no description of this is given since it is not relevant to the present invention.
Each of the repeaters includes an opto-electrical transducer for receiving light from an incoming optical fiber link, and converting that light into electrical form. The electrically conveyed signals are then amplified in a conventional electronic amplifier, and the amplifier's output applied to an electrical-optical transducer for conversion to optical form for launching into an outgoing optical fiber link.
A drawback to a system such as described above is that the failure of any one fiber link or any one repeater will disable the whole system.